1. Field of the Invention
This invention relates to an additive to aqueous paint. More particularly, it relates to an additive to aqueous paint for improving the wettability thereof for preventing coating defects such as craters, cissing and pinholes.
2. Prior Art
Although a great variety of paints are known in the art, most of currently used paints are solvent base paints containing organic solvents as diluents. To meet a growing demand for environmental protection, the paint industry tends toward conversion from solvent base paints causing air pollution to aqueous paints causing less pollution.
Aqueous paints are less polluting and ensure safe application since the diluent is non-toxic, non-dangerous water, but suffer from several drawbacks associated with water. The most serious drawback of aqueous paints is the likelihood of forming coating defects such as craters, cissing and pinholes due to the high surface tension of water. Known approaches for preventing such coating defects include the addition of (1) amphiphatic solvents such as alcohols and cellosolves, (2) anionic, cationic, nonionic and ampholytic surface-active agents, and (3) polyether-modified silicone compounds. These additives function to lower the surface tension of paint systems for improving their wettability to objects to be coated. Additives (2) and (3) are commercially available as aqueous paint additives. However, they are not fully satisfactory.